The Western diet, rich in fat and sugar, contributes to cardiovascular risk and alters the body metabolism, specifically through the modulation of the microbiome. Microbiome is considered the "second genome", functioning as an endocrine-like organ. Gut microbiota-derived metabolites, namely trimethylamine- N-oxide and short-chain fatty acids have been associated with atherosclerosis, vascular and cardiac diseases. Regarding trimethylamine- N-oxide, its association with cardiovascular disease is positive and dose-dependent. In contrast, short-chain fatty acids have been positively associated with the improvement of cardiovascular health. Algae probiotics can modulate gut microbiome, stimulating the growth of commensal micro-organisms with health benefits. Previous studies suggested that Spirulina Arthrospira platensis supplementation could improve blood lipid levels and lower blood pressure, revealing anti-inflammatory and antioxidant roles. Other probiotics that could be beneficial to gut microbiota are macroalgae or seaweed. Macroalgae are a rich source of components which may prompt bacterial diversity and abundance. The present prospective, randomized, three-armed parallel trial aims to generate good-quality evidence about the potential health effects and impact of Spirulina Arthrospira platensis (microalgae) and Gelidium corneum (macroalgae) supplements in humans. These participants will undergo 3 clinical evaluations: 2 before the beginning of micro- and macro-algae supplementation and the last one after 20 weeks of supplementation. The evaluation includes a vascular, nutritional and physical activity assessment, as well as blood, urine, saliva and stool collection for quantification of plasma biomarkers, oral and gut microbiota analysis, respectively.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
QUADRUPLE
Enrollment
150
Spirulina Arthrospira platensis (4 x \~500mg), taken twice daily as 2 capsules in the morning + 2 capsules in the evening
Gelidium corneum (4 x \~500mg), taken twice daily as 2 capsules in the morning + 2 capsules in the evening
Microcrystalline cellulose, silicon dioxide and dicalcium phosphate (4 x \~500mg), taken twice daily as 2 capsules in the morning + 2 capsules in the evening
Unidade Local de Saúde de São João
Porto, Portugal
RECRUITINGPlasma trimethylamine-N-oxide levels
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the between-group ratio of geometric means difference of the Log transformed plasma trimethylamine- N-oxide levels change from baseline to 20 weeks. The co-primary comparison will be Spirulina Arthrospira platensis versus Placebo and Gelidium corneum versus Placebo with a 2.5% alfa for each comparison.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Plasma short-chain fatty acids levels
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Gut microbiota
To assess the effect of the Spirulina Arthospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Systolic blood pressure
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Diastolic blood pressure
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Body weight
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Total cholesterol
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Low-density lipoprotein cholesterol
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
High-density lipoprotein cholesterol
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Lipoprotein A
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Triglycerides
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Interleukin-6
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Glucose
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Insulin
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Haemoglobin A1c
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Estimated Glomerular Filtration Rate
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Sodium
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Potassium
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
High-sensitivity C-reactive protein
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the following measures relative to the baseline measures.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Oral microbiota
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change of the oral microbiota relative to the baseline.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Pulse wave velocity
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on arterial stiffness. Measured by carotid-femoral pulse wave velocity using pulse wave analysis to assess arterial stiffness. Expressed in m/s. Higher values = greater arterial stiffness.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Intima-media thickness
To assess the effect of Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on vascular structure, measured by carotid intima-media thickness using cervical echo-Doppler ultrasound. Measured by cervical echo-Doppler ultrasound in the common carotid artery (automatic recording of 5 cycles). Expressed in mm. Lower values = better vascular structure.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Cerebral blood flow velocities
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on cerebral blood flow. Measured by transcranial color-coded duplex Doppler in middle cerebral arteries and posterior cerebral arteries. Expressed in cm/s. Higher values = greater blood flow velocity.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Cerebral blood flow resistance indexes
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on cerebral vascular resistance. Measured by transcranial color-coded duplex Doppler in middle cerebral arteries and posterior cerebral arteries. Expressed as resistance index (RI), calculated from Doppler waveforms. Higher RI = greater vascular resistance.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Cerebral vascular reactivity
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on cerebral vascular reactivity. Measured by transcranial color-coded duplex Doppler during a breathing manoeuvre. Expressed as % change in blood flow velocity in middle cerebral arteries and posterior cerebral arteries, in response to hypercapnia. Greater reactivity = better cerebrovascular function.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Breath-holding index
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on cerebrovascular reserve capacity. Measured by transcranial color-coded duplex Doppler in middle cerebral arteries and posterior cerebral arteries during a 20-second apnea manoeuvre. Expressed as index value. Higher BHI = better vascular reserve.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Neurovascular coupling (visual stimulation)
To assess the effect of the Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on neurovascular coupling. Measured by transcranial color-coded duplex Doppler during visual stimulation with a flickering checkerboard (10 Hz). Expressed as blood velocity change in middle cerebral arteries and posterior cerebral arteries recorded across cycles of 20 seconds stimulation (eyes open) and 20 seconds rest (eyes closed). Greater change = better neurovascular coupling.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Mediterranean diet adherence screener score
To assess the effect of Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change in adherence to the Mediterranean diet, as measured by the Mediterranean Diet Adherence Screener (MEDAS). The MEDAS is a 14-item questionnaire that evaluates food intake habits and frequency of consumption of specific foods. Each item receives 1 point for a positive response, resulting in a total score ranging from 0 to 14. Higher scores indicate greater adherence to the Mediterranean diet, with a score of ≥10 considered adherent.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
Total score of physical activity
To assess the effect of Spirulina Arthrospira platensis versus Gelidium corneum versus placebo on the percentage change in total physical activity score, as measured by the International Physical Activity Questionnaire - short version. This questionnaire includes 7 items assessing frequency and duration of physical activity during the past 7 days across different domains. Activities are weighted by metabolic equivalents (METs) (walking = 3, moderate = 4, vigorous = 8), and a total score is expressed as MET-minutes/week. Scores range from 0 to several thousand, with higher values indicating greater physical activity.
Time frame: Visit 1 (day 7 to day 30) and Visit 2 (20 weeks ± 15 days from Visit 1)
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